问题
选择题
These doctors are busy day and night, a cure for AIDS.
A．bringing on
B．pulling on
C．taking on
D．working on
答案
答案：D
动词短语辨析。bring on引起, 使发展, 提出；穿上；pull on继续拉；穿上；take on雇佣，呈现，承担；work on从事于，进行；句意：那些医生日夜忙碌，进行对艾滋病的治疗。
